Bruce E Dunn

U.S. Department of Veterans Affairs | VA · Office of Research and Development (ORD)

Background: Tissues respond to injury by releasing acute phase reaction (APR) proteins which regulate inflammation and angiogenesis. Among the genes upregulated in wounded tissues are tumor necrosis factor-alpha (TNFα) and the acute phase reactant orosomucoid-1 (ORM1). ORM1 has been shown to modulate the response of immune cells to TNFα, but its r...

The chick chorioallantoic membrane (CAM) subserves gas exchange in the developing embryo and shell-less culture affords a unique opportunity for direct observations over time of individual blood vessels to pharmacologic interventions. We tested a number of lipids including prostaglandins PGE(1&2) for vascular effects and signaling in the CAM. Appli...

Since mid-1996 we have operated a diagnostic robotic telepathology (TP) system at the Iron Mountain, Michigan, Department of Veterans Affairs Medical Center (VAMC) from the Milwaukee, Wisconsin VAMC, located some 220 miles away. No on-site pathologist is present in Iron Mountain. Instead, an experienced, well-trained pathologist assistant, under di...

Since mid-1996, we have operated a diagnostic robotic telepathology (TP) system at the Iron Mountain, MI, Department of Veterans Affairs Medical Center (VAMC) from the Milwaukee, WI, VAMC, located some 220 miles away. No on-site pathologist is present in Iron Mountain. Instead, an experienced, well-trained pathologist assistant, under direction of...

The Veterans Integrated Service Network (VISN) 12, headquartered in Chicago, Illinois, has implemented a telepathology network between the seven hospital laboratories located in three states linked by an economical, high-speed wide area network (WAN). In addition to telepathology, the WAN enables real-time teleradiology, telefluoroscopy, telenuclea...

Mohs micrographic surgery is a specialized surgical and pathologic technique for the treatment of high-risk cutaneous neoplasms. With this technique, small margins of normal appearing tissue surrounding the clinically apparent tumor are excised in successive stages and then processed via a fresh-frozen technique for immediate microscopic examinatio...

Aim of this paper is to describe the experimentations carried out to evaluate the diagnostic efficacy of a dynamic-robotic telepathology system for the delivery of pathology services to distant hospitals. The system provides static/dynamic features and the remote control of a robotized microscope over four ISDN lines. For evaluation purposes, 184 c...

Written by experts from around the globe "Telepathology" explains technical issues, digital information processing and collective experiences from practitioners in different parts of the world practicing a wide range of telepathology applications. This includes e.g. telepathology for gastrointestinal biopsy specimens, telepathology at the United St...

Shell-less culture of chick chorioallantoic membrane (CAM) of developing chicken embryos is a useful model to evaluate the effects of vascular agents. We assessed the response of CAM vessels to epoxyeicosatrienoic acids (EETs), derivatives of the essential fatty acid arachidonic acid, that have a number of important biological functions, including...

To achieve real-time connectivity between its 8 hopital-based laboratories, Veterans Integrated Service Network (VISN) 12, headquartered in Chicago, IL, has implemented a hybrid dynamic store-and-forward (HDSF) telepathology network that extends across portions of 3 states. The majority of diagnostic telepathology functions are provided to the 3 ho...

Telepathology is the practice of pathology at a distance by using video imaging and telecommunications. Significant progress has been made in telepathology. To date, 12 classes of telepathology systems have been engineered. Rapid and ultrarapid virtual slide processors may further expand the range of telepathology applications. Next-generation digi...

The crystal structure of Helicobacter pylori urease helps to explain how this enzyme contributes to bacterial survival in the acid environment of the human stomach.

H. pylori colonizes a hostile gastric environment where few other organisms can survive. Its prolonged presence in this milieu is associated with gastric diseases such as gastritis, ulcers, and gastric cancer (5, 20, 58–60). One of the basic features that may aid the bacterium to colonize this niche is a unique PG with a low level of cross-linking,...

Complete DNA sequencing of the H. pylori genome has allowed sequence-similarity comparisons with other gram-negative bacteria. Investigations are in progress to confirm the function of homologous molecules in transcriptional and translational processes. These studies demonstrate the universality of many aspects of structure and function in the gram...

The Veterans Integrated Service Network (VISN)-12, headquartered in Chicago, has implemented a telepathology network between the eight VISN-12 hospital laboratories and Loyola University Medical School linked by an economical, high-speed wide-area network (WAN). Implementation of the WAN has reduced monthly telecommunications costs in VISN-12 by ap...

Telepathology is gaining acceptance as a mode of providing pathology services to remote sites, but its economic feasibility is unknown. A dynamic robotic telepathology service between the Veterans Affairs Medical Center, Iron Mountain, MI, and the Veterans Affairs Medical Center, Milwaukee, WI, provides diagnostic services for routine and frozen se...

The Helicobacter pylori genome encodes four penicillin-binding proteins (PBPs). PBPs 1, 2, and 3 exhibit similarities to known PBPs. The sequence of PBP 4 is unique in that it displays a novel combination of two highly conserved PBP motifs and an absence of a third motif. Expression of PBP 4, but not PBP 1, 2, or 3, is significantly increased durin...

The aim of this study was to assess the yield of antral biopsies performed via unsedated transnasal esophagogastroduodenoscopy, a technique that does not require conscious sedation with its concomitant costs and complications, for documentation of Helicobacter pylori eradication. Nineteen patients who were previously CLO test positive on convention...

To determine whether diagnostic concordance, case deferral rate, and/or time required to review slides changed significantly as telepathologists gained additional experience using a hybrid dynamic/store-and-forward (HDSF) telepathology (TP) system on the 2000 cases following an initial 200 consecutive surgical cases, previously reported. Gross surg...

Helicobacter pylori, an important etiologic agent in a variety of gastroduodenal diseases, produces large amounts of urease as an essential colonization factor. We have demonstrated previously that urease is located within the cytoplasm and on the surface of H. pylori both in vivo and in stationary-phase culture. The purpose of the present study wa...

Helicobacter pylori is the causative agent of most cases of gastritis. Once acquired, H. pylori establishes chronic persistent infection; it is this long-term infection that, is a subset of patients, leads to gastric or duodenal ulcer, gastric cancer or gastric MALT lymphoma. All fresh isolates of H. pylori express significant urease activity, whic...

Rural hospitals generally lack staffing with infectious disease specialists or pathologists. Without on-site pathologists, the range of microbiology services offered by clinical laboratories may be limited as well. To study the feasibility of using static-image telepathology to evaluate Gram stains of microbiologic preparations. In this retrospecti...

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the...

Helicobacter pylori is a spiral, gram-negative bacterium which causes chronic gastritis and plays a critical role in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori expresses significant urease activity which is an essential virulence factor. Since a significant fraction of urease activity is located on the surface of the b...

The aim of this study was to compare the Pyloritek test (a 1-h rapid urease test) to the widely used CLO test. Seventy-one patients undergoing upper endoscopy were studied. All patients gave informed consent. A single antral biopsy specimen was obtained for the CLO test, and another was obtained for the Pyloritek test. Additional specimens were obt...

Routine surgical pathology review by telepathology could be an important service component of multi-institutional pathology laboratory systems. Such service networks would increase access for rural hospitals without on-site pathologists to a broader range of pathology services on a daily basis. In this clinical trial, we analyzed the diagnostic acc...

In this retrospective study, we assess the accuracy, confidence levels, and viewing times of two generalist pathologists using both dynamic-robotic telepathology and conventional light microscopy (LM) to render diagnoses on a test set of 100 consecutive routine surgical pathology cases. The objective is to determine whether telepathology will allow...

Helicobacter pylori produces large amounts of urease presumably to be prepared for the rare event of a sudden acid exposure. The hypothesis that H pylori is acid sensitive and protein production is inhibited by low pH was examined. H pylori or its soluble enzymes were incubated buffered or unbuffered at a pH ranging from 2-7 in the presence of 5 mM...

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and is associated with peptic ulcer disease, gastric carcinoma, and gastric lymphoma. The bacterium is characterized by potent urease activity, thought to be located on the outer membrane, which is essential for survival at low pH. The purpose of the present study was t...

Abscess and empyema fluid supernatants have zinc-reversible antimicrobial activity that is thought to be due to calprotectin, a calcium- and zinc-binding protein present within neutrophil cytoplasm. The present studies were undertaken to determine if calprotectin isolated from human empyema fluid supernatants demonstrated similar antimicrobial acti...

In 82 patients who underwent gastroduodenoscopy, acute and chronic gastric mucosal inflammation was scored for severity, and systemic humoral immune responses to Helicobacter pylori antigens were assessed by enzyme-linked immunosorbent assays. On the basis of culture, gastric histology, and serologic evaluation, 33 patients were classified as H. py...

Increasing evidence suggests that Helicobacter pylori plays an important role in the pathogenesis of duodenal ulcer disease. The bacterium is present in the gastric antrum in over 90% of individuals with duodenal ulcer1,2, and eradication of the organism decreases recurrence of duodenal ulcers significantly3,4. However, the pathogenic mechanisms wh...

Infection by Helicobacter pylori is the causative agent of chronic active gastritis in humans1–3; chronic infection with this bacterium appears to play an important role in gastric and duodenal ulcers, and in at least some forms of gastric carcinoma and gastric lymphoma4,5. Essentially all strains of H. pylori are associated with gastric inflammati...

There is general agreement that motility, urease activity, and association with gastric mucosal cells are important virulence factors of H. pylori. Urease activity is perhaps the best characterized of these factors. Presumably, urease activity creates a "cloud" of ammonia around the bacterium, thus neutralizing the lethal effects of gastric acid. M...

The following study was conducted to determine the prevalence of hepatitis C virus (HCV) infection among local veteran patients. We used an enzyme immunoassay (EIA) (Abbott Diagnostics HCV, Abbott Park, III) to test sera from 323 patients; 203 samples were from patients with abnormal liver function (ALF) and 120 were from patients with normal liver...

We report a case of ehrlichiosis in a 72-year-old man who developed extreme lethargy, acute renal failure requiring hemodialysis, and respiratory insufficiency requiring intubation. Lumbar puncture performed on the second day of hospitalization revealed significant cellular pleocytosis. Ehrlichia morulae were tentatively identified in mononuclear c...

Helicobacter pylori is associated with gastritis and peptic ulcer disease in humans. We have identified a homolog of the chaperonin cpn60 family of heat shock proteins in H. pylori, referred to as Hp54K. Hp54K, purified from water-extractable H. pylori proteins, migrated as a single band at 54 kDa by sodium dodecyl sulfate-polyacrylamide gel electr...

A recombinant 60 kDa Brucella abortus protein expressed in Escherichia coli was recognized in immunoblots by sera from mice experimentally infected with B. abortus and a dog experimentally infected with B. canis. Sera from humans and dogs with naturally acquired brucellosis also recognized this protein, which was designated BA60K. The gene encoding...

Helicobacter mustelae is a urease-rich bacterium associated with gastritis in ferrets. The ureases of H. mustelae and Helicobacter pylori, a bacterium implicated in human gastritis, share many characteristics. Helicobacter sp. ureases appear to be unique among bacterial enzymes in exhibiting submillimolar Km values and in being composed of two subu...

An in vitro assay using immunofluorescence and flow cytometry for quantitative assessment of the adherence of Helicobacter pylori to cultured human gastric carcinoma (KATO III) cells was developed. Adherence was rapid, saturable, energy dependent, mannose resistant, and significantly inhibited by fetuin, a glycoprotein containing N-acetylneuraminyl...

Lactoferrin and transferrin have antimicrobial activity against selected Gram-negative bacteria, but the mechanism of action has not been defined. We studied the ability of lactoferrin and transferrin to damage the Gram-negative outer membrane. Lipopolysaccharide release by the proteins could be blocked by concurrent addition of Ca2+ and Mg2+. Addi...

Serologic studies in developed countries indicate that Helicobacter (formerly Campylobacter) pylori infection is uncommon until the third decade of life and achieves a peak prevalence of 50% in the seventh decade. In developing countries the epidemiology of H. pylori has not well been described. A sensitive and specific serologic assay for H. pylor...

Urease was purified 112-fold to homogeneity from the microaerophilic human gastric bacterium, Helicobacter pylori. The urease isolation procedure included a water extraction step, size exclusion chromatography, and anion exchange chromatography. The purified enzyme exhibited a Km of 0.3 +/- 0.1 mM and a Vmax of 1,100 +/- 200 mumols of urea hydrolyz...

Urease was purified 112-fold to homogeneity from the microaerophilic human gastric bacterium, Helicobacter pylori. The urease isolation procedure included a water extraction step, size exclusion chromatography, and anion exchange chromatography. The purified enzyme exhibited a Km of 0.3 +/- 0.1 mM and a Vmax of 1,100 +/- 200 mumols of urea hydrolyz...

Breve informacion sobre la presencia del Vibrio cholerae en el agua de Colorado, EEUU. La nota dirigida al editor provee informacion adicional a la aparecida en la misma revista, volumen 159 de 1989, sobre la bacteremia y los casos presentados

Whole-cell, outer-membrane protein, flagellum-associated antigens and partially purified urease of Campylobacter pylori were analyzed by two-dimensional gel electrophoresis. C. pylori strains were readily distinguished from strains of Campylobacter jejuni, C. coli, and C. fetus by absence of major outer membrane proteins with Mrs of 41,000 to 45,00...

In an ongoing study of the changes that occur in platelet concentrates during storage, we investigated two 28-26-Kd proteins designated SP-1 and SP-2, respectively, which increase markedly during blood-bank storage of platelet concentrates at room temperature. Formation of SP-1 and SP-2 was inhibited by storage at 4 degrees C as well as by treatmen...

In an ongoing study of the changes that occur in platelet concentrates during storage, we investigated two 28–26-Kd proteins designated SP–1 and SP–2, respectively, which increase markedly during blood-bank storage of platelet concentrates at room temperature. Formation of SP–1 and SP–2 was inhibited by storage at 4 degrees C as well as by treatmen...

Carboxymethyl dextrans (CM-Ds) were used on an HPLC ion-exchange column to obtain significantly enriched alkaline phosphatase (EC 3.1.3.1) from a sample of Escherichia coli periplasmic space proteins without significant loss of enzymatic activity. The ability of CM-Ds to separate alkaline phosphatase even when the column was 80-85% saturated with p...

We characterized outer membrane proteins (OMPs) from selected Campylobacter jejuni, C. coli, and C. fetus strains by two-dimensional gel electrophoresis (2DGE), using isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and by immunoblotting with immune rabbit serum. The flagellar band with a molecular mass...

The changes in thrombocyte proteins during 22 degrees C storage of platelet concentrates (PC) were studied. To prepare a reference protein "map" of stored PC, platelet samples were taken on days 1, 7, and 21. The platelet proteins were separated by isoelectric focusing (first-dimension) followed by second-dimension polyacrylamide gradient gel elect...

We characterized outer membrane proteins (OMPs) from selected Campylobacter jejuni, C. coli, and C. fetus strains by two-dimensional gel electrophoresis (2DGE), using isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and by immunoblotting with immune rabbit serum. The flagellar band with a molecular mass...

RNA sequence analysis has been used to examine the phylogenetic position and structure of the genus Campylobacter. A complete 5S rRNA sequence was determined for two strains of Campylobacter jejuni and extensive partial sequences of the 16S rRNA were obtained for several strains of C. jejuni and Wolinella succinogenes. In addition limited partial s...

Chick embryos grown in shell-less culture are calcium-deficient by 9 days and retarded in growth by 13 days of incubation (Dunn and Boone, Poult. Sci., 56:662-672, 1977). To determine whether addition of exogenous calcium might stimulate growth and/or survival of cultured embryos, calcium supplementation was attempted. Calcium supplementation betwe...

The chorionic epithelium of the developing chick embryo consists of two major cell types, villus cavity (VC) and sinus-covering (SC) cells. Ultrastructurally, VC cells contain apical microvilli with numerous underlying vesicles, whereas SC cells possess thin cytoplasmic processes (containing occasional vesicles) overlying adjacent blood sinuses. Th...

By removing the shell membranes from the chorioallantoic membrane, the chorion is damaged, as visualized by electron microscopy, and rendered permeable, as evidenced by penetration of horseradish peroxidase and increased inhibition of the allantoic Na+-K+ pump by ouabain applied on the chorionic side. The short-circuit current (SCC) of this functio...

The ultrastructure of the parathyroid glands was studied in chick embryos developing normally in ovo or in shell-less culture (after removal of the eggshell). Shell-less chick embryos are significantly hypocalcemic relative to their in ovo counterparts. At 12 days of incubation, the parathyroid glands of shell-less embryos contain more lipid and sh...

It is shown that carboxymethyldextrans can be used to displace proteins from high-performance ion-exchange columns. The high resolving power of the method is demonstrated by the total separation of the A and B genetic variants of the β-lactoglobulins, which have only 0.1 pH difference in their isoelectric points. The separation of up to 12.8 mg of...

Direct interaction of the chorioallantoic membrane (CAM) with the overlying Ca2+-rich shell membranes is necessary for maximal stimulation of Ca2+ transport by the CAM. First, CAM developing in the absence of the shell and shell membranes (in shell-less culture or in artificial air space preparations), which demonstrates normal cytodifferentiation,...

Shell-less culture involves culturing chick embryos with associated yolk and albumen outside of the eggshell and shell membranes. The technique allows direct access to and continuous observation of cultured embryos almost to the time of hatching. The plastic wrap/culture tripod technique described in this paper allows normal embryonic growth and di...

Collagen is a major constituent of the extracellular matrix (ECM) of the early developing heart. The role of mature cross-linked collagen has not been demonstrated in cardiac morphogenesis, although investigators using other developmental systems have suggested that collagen can act as an inducer. The injection of 500 μg of BAPN (beta-aminopropioni...

In order to determine whether the chorionic epithelium (CE) of the chorioallantoic membrane (CAM) of chick embryos maintained in shell-less culture might be suitable for studies of calcium translocation and/or tissue grafting, membranes from 10- to 18-day embryos were studied histologically using Nomarski differential interference optics on living,...

A photographic study of development of chick embryos cultured in vitro was conducted in order to demonstrate the relationship between embryos and extraembryonic membranes during culture. Survival of embryos in this system has been extended to 21 days of total incubation (3 days in shell plus 18 days in vitro) and development to Hamburger-Hamilton s...

In order to assess mineral uptake by chick embryos cultured outside of the shell, growth and mineral (Ca, Mg, K, Na) composition of control and cultured embryos and total egg contents (embryo plus residual egg contents) were measured from 8 through 21 days of incubation. At day nine and thereafter, cultured embryos contained significantly less Ca a...

An improved technique is described for in vitro culture of the chick embryo from three days through 21 days of total incubation (three days in shell plus 18 days in culture). Mean survival time for cultured embryos is 18 days of total incubation, and mean morphological stage is Hamburger-Hamilton stage 41 (15 days). Mean measurements of wet weight,...

A technique is described whereby avian egg contents removed from the shell after 72 hours of normal incubation may be successfully cultured for extended periods of time (81% for 15.5 days), many of the embryos reaching Hamilton-Hamburger Stage 40–41 (14–15 days). Egg contents are suspended in commercial plastic wrap held in place in culture vessels...

acute andchronic gastric mucosal inflammation was scored forseverity, andsystemic humoral immuneresponses toHelicobacter pylori antigens wereassessed by enzyme-linked immunosorbent assays. Onthebasis ofculture, gastric histology, andserologic evaluation, 33 patients wereclassified asH.pylori infected and36wereclassified asuninfected. Thirteen patie...